Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!ames!amdahl!pacbell!att!chinet!les
From: les@chinet.chi.il.us (Leslie Mikesell)
Newsgroups: comp.unix.wizards
Subject: Re: unix question about stdin
Message-ID: <8283@chinet.chi.il.us>
Date: 24 Apr 89 04:23:31 GMT
References: <3398@udccvax1.acs.udel.EDU>
Reply-To: les@chinet.chi.il.us (Leslie Mikesell)
Organization: Chinet - Public Access Unix
Lines: 17

In article <3398@udccvax1.acs.udel.EDU> conan@vax1.acs.udel.EDU (Robert B Carroll) writes:
>Once stdin is closed, how do you open it up again so that
>all the stdio functions(scanf, gets etc. etc. etc.) will work
>via a terminal keyboard? to explain it in more detail, my C
>program:

>1) reads user info typed in from keyboard
>2) does a freopen and acts like a file is now standard input
>3) then i need to 'make' standard input be the keyboard so that
>   i can get info typed in from the keyboard again.

One way is to dup(2) the original file descriptor to hold a copy before
the freopen.  To get it back, close(0); dup(copy);.  There might be
some problems with buffered input if you had not read to EOF on the
alternate stream.

Les Mikesell